Method of inducing solvency and toxicity



Patented July 28, 1942 UNITED STAT ES PATENT OFFICE METHOD OF'INDUCING SOLVENCY AND TOXICITY No'Drawing. Application July 13, 1940, SeriaI No. 345,441

4 Claims.

The present invention relates tothe joint production of solvents andwoodpreserving oils.

Mor specifically the present invention relates to the joint production of solvents and wood preservatives from high boiling fractions of tars of aromatic content; suchhigh boiling fractions include topped tars, residual tars, high.- boiling fractions, residues, polymerized fractions, and pitches of various nature. Thetars from which said high boiling fractions are recovered are tars of aromatic content and include as an example, tars derived from coal, wood, and petroleum. Such tars include the well known aromatic tars of petroleum origin.

An object of the present invention is a joint production of solvents and wood preserving oils of lowered boiling range from high boiling tar fractions of higher boiling range, saidconversion being characterized by controlling process variable to the end that said solvents have an aromaticity in the order of 50% or more; and the wood preservatives have a toxicity inexcess of their parent material;

As is wellknown in the art, to produce a solvent having an aromatic content of 50% or more from aromatic tars it is necessary to so coordinate process variables that the aromatic nuclei of the starting material is'protected against excessive rupture and subsequent degradation. It is equally well understood that in the provision of a Wood preservativefrom a givenstarting. material wherein said preservative is more toxic than the parent material, it is necessary also to protect the'aromatic nucleiof the starting material against excessive rupture and subsequent degradation.

By the process of' the present invention", the starting materials are subjected to theaction of hydrogen, while contacting a catalyst adapted to influence the decomposition of oxygenated organic compounds contained in said starting ma-- terial, whereby to enhance the induction of? solvent fractions and toxicity.

The starting materials of the present process are substances of a questionable-value and it has long been a deside'ratum in the art to convert said starting materials to products of' greater value.

The process or the present invention is characterized by subjecting the starting materials to the action of hydrogen with time, temperature and pressure so controlled that no substantial deposition of carbonaceous increment is induced.

By the phrase no substantial deposition of carbonaceous increment is meant that deposi-- 55 tion of high carbon material including coke that results from too high temperature, and does not include carbon deposition inherent to theprocess. The following examples will serve to illustrate modes of practicing the present invention.

Example 1.A coal tar residuum characterized by oxygen content and boiling substantially 15% at 355 C. and having aspecific gravity in the order of 1.20 was charged to high pressure autoclave and subjected to th actionof hydrogen, while contactinga catalyst of molybdenum sulfide and asmall amount of iodoformj, at a temperature of 385 C. and a pressure of 350 atmospheres for a period of one and one-half hours. The beneficiatedmaterial was fractionalliy distilled to an upper limit Of 355 C. to provide the material boiling below 200 C; as a distillate having in the order of 50% aromaticity or more and the portion boiling between ZOO-355 C. as a wood preserving oil more toxic than its parent material; By controlling the reaction as named no substantial percentage of carbonaceous deposition was noted; and as regards the Wood preserving fraction, toxicity was also induced as a result of the joint decomposition of oxygenated compounds as influenced by the presence ofsaid halogen-derivedcatalyst, and by hydrogenation. The presence of said halogenderivedcatalyst influenced the elimination of oxygen and/or hydrogenation of carbon to oxygen bonds, thereby assisting in induction of solvents of' substantial aromati'cityand wood pre serving oils of enhanced toxic value.

Thus, the present invention will be seen to provide a processfor the conversion of high boiling tar fractions having little or no solvency, and little or no toxicity, to solvents and wood preservatives; said conversion being effected by the controlled action of hydrogen whereby to produce solvents of good aromaticityand wood preserving oils-of enhanced toxic value the while precluding substantial carbon deposition; said controlledhydrogenation being further characterized by being effected in the presence of a catalyst adapted to influence the decomposition of oxygenated compounds contained in starting material.

There is no inflexible point of fractionation between the solvents and the wood preserving oils of the present invention, in as much as solvents currently on the market have varied end points, and wood preserving oils of commercial acceptance have varied initial boiling points.

In the fractionation of the beneficiated material, e end point of the solvent substantially f corresponds to the initial boiling point of the wood preserving oil of induced toxic characteristics.

As illustrating this, the tubular data shown below are the end points of commercially accepted solvents, and the initial boiling points of commercially accepted wood preserving oils.

Commercial solvent: End point, C.

Benzol 120 Toluol M 150 High flash naphtha 200 Heavy naphthas Above 200 Commercial wood preservative: ,I. B. P .C.

American Wood Preservers Association 5% at 2l0 American Wood Preservers Association 1% at 210 American Wood Preservers Association l /2 at 235 Prussian Ry 3% at 150 Neville Shingle Stain Oil 150 Southern Pine Shingle Stain Oil 92 Example 2.An aromatic tar fraction boiling substantially 3% at 380 C. was passed through a high pressure reaction vessel, while contacting a catalyst consisting of molybdenum sulfide and tin chloride, at a pressure of 325 atmospheres and a temperature of 385 C. while flowing with said tar fraction 20,000 cubic feet hydrogen per barrel feed stock. Time of contact substantially one hour. The beneficiated material was fractionally distilled to an upper limit of 375 C. to

recover the portion distilling up to 235 C. as a solvent having an aromaticity in the order of 50% or higher, and the portion distilling between substantially 235 C. and 375 C., as a wood preserving distillate of enhanced toxic value.

Example 3.-A toppedtar boiling substantially above 250 C. was passed through ,a high pressure reaction vessel while contacting catalytic material comprising cobalt sulfide and tin chloride,

and while passing therewith eleven thousand cubic feet hydrogen per barrel feed stock. Pressure 400 atmospheres, temperature 405 0,, time of contact 1 hours. was distilled to an upper limit of 270 C. toprovide the distillate as a solvent having an aromaticity near the order of 50% or more, with the residue therefrom serving as a substitute for wood preserving oils of the carbolineum boiling range, the fraction above 270 C. for use as a wood preserver being characterized by a toxicity in excess of a comparable boiling out from its parent material.

All catalysts effective in the presence of hydrogen for aforesaid purposes are usable in conjunction with catalysts of halogen origin. As

for instance, chromium, molybdenum, vanadium, uranium, cobalt, copper and their compounds as sulphides or oxides; promoted or not; with The beneficiated material In the foregoing examples the residues resulting from distillation recovery of a wood preserving oil from the beneficiated tar fractions may be used as an article of commerce or recycled for further treatment in accordance with a process of the present invention.

The starting materials of the present invention are characterized by content of oxygenated compounds; said oxygenated compounds, under the influence of a catalytic material selected from the group consisting of halids, and halogens, and derivatives thereof, and while in the presence of hydrogen, are decomposed whereby to provide enhancement of toxicity induction.

Example 4.-A stripped tar boiling substantially above 240 C. and characterized by content of oxygenated compounds was subjected to the action of hydrogen at 400 C. and a pressure of 350 atmospheres for a period of one and onehalf hours. Catalyst, molybdenum sulfide and iodoform. The beneficiated material was fractionally distilled to an upper limit of 360 C, the fraction boiling below 200 C. comprising the solvent of the present invention and having an aromaticity of not substantially less than 50%, with the fraction boiling substantially between 200 C. and 360 C. serving as the wood preservative of the present invention having a toxic value in excess of its parent material. The residue incidental to said distillation may be recycled if desired, or used as an article of commerce of value because of its enhanced properties.

A mention has been made of employing a material selected from the group of halids, halogens, or derivatives thereof, for the purpose of influencing the decomposition of oxygenated compounds contained in the starting material. Said decomposition infiuencer may be used alone or in the presence of catalyst material adapted to further influence hydrogenation. When usin said decomposition infiuencer alone, said infiuencer may be added to the starting material in small amounts, as for instance ,one tenth of one percent or more, as based on the starting ,material. Whensaid decomposition influencer is used with or incorporated in other catalyst, ,said influencer may represent as much as 50% of the total catalyst, or more.

When using a starting material of inordinately high carbon content it may be desirable at times to at least partially depolymerize the molecular complexes contained therein by ,aidof'a solvent, and said solvent may be used in small amounts or even in amounts equal to thevolume of the starting material, or more. 7

The preferred temperatures of the process are chosen from the range above 300 C., however, lower temperatures are usable. Pressures of200 atmospheres and above are preferred, as for 'instance 300 or 400 atmospheres; however, lower pressure is usable. Using average starting materials, as for instance a soft pitch obtained from coal tar, when employing a temperature of 400 C. and a pressure of 300' atmospheres, in the order of one hour will serve to .induce vasubstantial percentage of the solvents and wood preservatives of the present invention without sub stantial carbon deposit as aforestated. The time element cannot be stated as an-arbitrary figure because of the variation instarting materials and the wide latitude of possible-coordinations .of pressure and temperature. Thus, the required time is that period necessary to induce .the ,predetermined percentage of, said solvent and wood preservative increment when coordinated with the temperature and pressures chosen to preclude substantial carbon deposit.

By the term beneficiated as used herein and in the appended claims is meant the starting material at least once subjected to the action of hydrogen in accordance with the present process.

Viewed broadly the present invention provides a process for the joint conversion of high boiling tar fractions to solvents having an aromaticity of at least in the order of 50%, and wood preserving oils of induced toxicity, said conversion being characterized by subjecting said starting materials to the action of hydrogen while contacting a catalyst capable of influencing decomposition of oxygenated compounds.

Minor changes may be made without departing from the spirit of the invention. In the claims aifixed to this specification no selection of any particular modification of the invention is intended to the exclusion of other modification thereof.

I claim:

1. In the joint production of solvents and wood preservatives of induced solvency and added toxicity the process which comprises: subjecting aromatic tar fractions containing oxygenated compounds and boiling predominantly above 355 C. selected from the group consisting of residues, pitches, residual tars, stripped tars, topped tars and petroleum aromatic tars to the action of hydrogen; precluding substantial rupture and subsequent degradation of aromatic nuclei by coordination of time, temperature and pressure, the while increasing induced solvency and added toxicity by inclusion as catalytic material a sulfide of a metal and iodoform; and dividing the treated material whereby to provide a relatively low boiling solvent having an aromatic content not substantially less than 50%, and a relatively high boiling oil of the wood preserving type boiling above and contiguous to said solvent, said wood preserving type oil having an initial boiling point below 220 C. and being further characterized by no greater percentage of material boiling below 210 0., nor a greater percentage of materials boiling between the initial point and a specified temperature than is permitted by specifications accepted in the trade for a tar-derived wood preservative.

2. The process of claim 1 wherein the oil of wood preserving type is recovered as a distillate.

3. The process of claim 1 wherein the oil of wood preserving type is recovered as a residue.

4. In the joint production of solvents and wood preservatives of induced solvency and added toxicity, the process which comprises: subjecting aromatic tar fractions containing oxygenated compounds and high molecular substances, and boiling predominantly above 355 0. selected from the group consisting of residues, pitches, residual tars, stripped tars, topped tars and petroleum tars to the de'polymerizing action of a solvent and thereafter reducing the depolymerized mass with hydrogen; precluding substantial rupture and subsequent degradation of aromatic nuclei by coordination of time, temperature and pressure, the while increasing induced solvency and added toxicity by inclusion as catalytic material a sulfide of a metal and iodoform; and dividing the treated material whereby to provide a relatively low boiling solvent having an aromatic content not substantially less than 50%, and a relatively high boiling oil of the wood preserving type boiling above and contiguous to said solvent, said wood preserving type oil having an initial boiling point below 220 C. and being further characterized by no greater percentage of materials boiling below 210 C., nor a greater percentage of materials boiling between the initial point and a specified temperature than is permitted by specifications accepted in the trade for a tar-derived wood preservative impregnant.

JACQUELIN E. HARVEY, JR. 

